i'm installing a bathroom in a basement finish. i've roughed in all the copper but for one last connection. i have to cut the existing supply lines to the rest of the house to feed my new copper. the lines to which i am going to tap are coming off the water heater (that's the most convenient location. do you have any tips on cutting into these lines without dousing the water heater. i can drain a lot of the water from the system through the washing machine but there will still be some in there when i cut.